Cyrus IMAP HOWTO
Aurora Skarra-Gallagher (Community Vision)
v1.3, 11 October 2000
A comprehensive guide to installing, configuring, and running Cyrus
Imap and Cyrus Sasl
______________________________________________________________________
Table of Contents
1. About this HOWTO
1.1 Copyrights and Trademarks
1.2 Feedback
1.3 CHANGES
1.4 Document Conventions
2. Introduction to IMAP
2.1 What is IMAP?
2.2 IMAP vs. POP
2.3 Cyrus IMAP vs. Washington IMAP
3. Obtaining the Files
3.1 Cyrus Imap Homepage
3.2 Downloading the files
4. Different SASL Authentication Methods
4.1 sasldb
4.2 LDAP
4.3 PAM
4.4 kerberos_v4
5. Cyrus SASL
5.1 Uncompress
5.2 Building the files
6. Cyrus IMAP Installation
6.1 Uncompress
6.2 A note on com_err.h
6.3 Configure
6.4 Adding the default user
6.5 Building the files
7. Cyrus IMAP Configuration
7.1 Editing conf files
7.2 Creating the necessary directories
7.3 More configuration file editing
7.4 If you use postfix instead of sendmail
8. Cyrus IMAP Implementation
8.1 Add the cyrus administrator
8.2 Testing Cyrus IMAP
8.3 Setting up users
8.4 Delivery database pruning
8.5 Finishing up
9. Troubleshooting
______________________________________________________________________
1. About this HOWTO
1.1. Copyrights and Trademarks
(c) 2000 Aurora Skarra-Gallagher
This section was copied from the HOWTO-HOWTO:
This manual may be reproduced in whole or in part, without fee,
subject to the following restrictions:
· The copyright notice above and this permission notice must be
preserved complete on all complete or partial copies
· Any translation or derived work must be approved by the author in
writing before distribution.
· If you distribute this work in part, instructions for obtaining the
complete version of this manual must be included, and a means for
obtaining a complete version provided.
· Small portions may be reproduced as illustrations for reviews or
quotes in other works without this permission notice if proper
citation is given. Exceptions to these rules may be granted for
academic purposes: Write to the author and ask. These restrictions
are here to protect us as authors, not to restrict you as learners
and educators. Any source code (aside from the SGML this document
was written in) in this document is placed under the GNU General
Public License, available via anonymous FTP from the GNU archive.
1.2. Feedback
Comments (especially corrections) can be sent to
asg@CommunityVision.com
1.3. CHANGES
· v1.3: inetd.conf error fix, authentication information added, more
troubleshooting info
· v1.2: SASL Config error fix, new postfix configuration, and
database pruning (thanks, Jernej)
· v1.1: Fixed sendmail.mc configuration file error and added IMAP
information to the introduction.
1.4. Document Conventions
· Italics signifies a directory
· This font signifies instructions to be ran at the command line
2. Introduction to IMAP
2.1. What is IMAP?
This definition is from the ComputerUser.com High-Tech Dictionary
:
Internet Message Access Protocol. A protocol that allows a user to
perform certain electronic mail functions on a remote server rather
than on a local computer. Through IMAP the user can create, delete, or
rename mailboxes; get new messages; delete messages; and perform
search functions on mail. A separate protocol is required for sending
mail. Also called Internet Mail Access Protocol.
2.2. IMAP vs. POP
IMAP allows the user to read email from many different locations and
accounts because email folders are stored on the server, locally, at
the home or the office, for instance. Even saved and read messages are
stored on the IMAP server. POP only stores new unread messages on the
server, and the read and saved messages are stored locally. To force
POP to not delete email once it has been read can create many copies
of the same email, creating a waste of space and confusion. However,
IMAP is usually more complicated to set up. If you only have one email
account, POP is most likely your best choice. If you want to access
more than one account, from different locations, IMAP will probably
serve you most efficiently.
2.3. Cyrus IMAP vs. Washington IMAP
Cyrus has its own mailbox database which is standalone and increases
performance, whereas Washington uses the stanard UNIX mailbox format,
which was designed for a smaller set of users. Washington is portable
to more UNIX and non-UNIX systems than Cyrus. The main difference is
that with Cyrus, you don't have to add new users to your linux box
(i.e. in /etc/passwd) to add new mail users, and with Washington, you
do.
3. Obtaining the Files
3.1. Cyrus Imap Homepage
The homepage is currently located at:
http://asg.web.cmu.edu/cyrus/imapd
3.2. Downloading the files
You will need both IMAP and SASL. Download the latest files here:
ftp://ftp.andrew.cmu.edu/pub/cyrus-mail
Download cyrus-imapd-X.X.X.tar.gz and cyrus-sasl-X.X.X.tar.gz (where
X.X.X is the latest release) into your temporary directory.
I will use /temp as the directory I've uncompressed the files under
for the rest of the examples.
4. Different SASL Authentication Methods
4.1. sasldb
This is the default method of authentication. It stores usernames and
passwords in the SASL secrets file sasldb. In this HOWTO, I assume you
are using the sasldb method of authentication.
4.2. LDAP
The following definition came from the OpenLDAP website. Lightweight
Directory Access Protocol (LDAP) is an open-standard protocol for
accessing information services. The protocol runs over Internet
transport protocols, such as TCP, and can be used to access stand-
alone directory servers or X.500 directories. This method isn't
discussed in this HOWTO, but here is a link to a page with patches and
info:
http://www.openldap.org/faq/data/cache/428.html
4.3. PAM
Not enough info to document. Email me if you have some.
4.4. kerberos_v4
Not enough info to document. Email me if you have some.
5. Cyrus SASL
5.1. Uncompress
Here we untar and gunzip the file in a single step.
1. cd /temp
2. tar -zxvf cyrus-sasl-X.X.X.tar.gz
3. cd cyrus-sasl-X.X.X
5.2. Building the files
For most purposes, the following set of instructions works fine. If
you would like to examine the other configuration options, type
./configure --help | more
1. ./configure
2. make
3. make install
If you don't want your password check to be the default sasldb, you
must specify which one of PAM, kerberos_v4, passwd, shadow you wish to
use. If PAM is the authentication you desire for example, you would
type:
./configure --with-pwcheck_method=PAM
instead of the ./configure line above
6. Cyrus IMAP Installation
6.1. Uncompress
The following commands will tar and gunzip cyrus IMAP under /temp.
1. cd /temp
2. tar -zxvf tar/cyrus-imapd-1.6.24.tar.gz
3. cd cyrus-imapd-1.6.24
6.2. A note on com_err.h
When I tried to install cyrus IMAP, I got errors regarding the file
com_err.h. My com_err.h was located in /usr/include/et. It needs to
reside in /usr/include. Run the following command to make sure it is
in the correct location:
locate com_err.h
This will show you where the file is. If it is under /usr/include, you
can skip to the next section. If it is in another directory, just copy
it to /usr/include. If it doesn't exist, download it here:
http://www.ludd.luth.se/~jnilsson/cvsweb/cvsweb.cgi/src/contrib/com_err
.
6.3. Configure
./configure --with-auth=unix
6.4. Adding the default user
Cyrus requires a user to own its files. The default user is cyrus. The
following command adds a user cyrus with the group of "mail"
useradd -g mail cyrus
You'll want to set the password for user cyrus.
passwd cyrus
Type in the password you desire cyrus to have each time you are
prompted
6.5. Building the files
1. make depend
2. make all CFLAGS=-O
3. make install
That's it! You're ready to configure Cyrus IMAP.
7. Cyrus IMAP Configuration
7.1. Editing conf files
1. Edit /etc/syslog.conf and add the following lines at the bottom:
local6.debug /var/adm/imapd.log
auth.debug /var/adm/auth.log
2. Edit a new file /etc/imapd.conf and place in it the following
lines:
configdirectory: /var/imap
partition-default: /var/spool/imap
admins: cyrus root
srvtab: /var/imap/srvtab
allowanonymouslogin: no
sasl_passwd_check: shadow
If you don't want your password check to be the default sasldb, you
must specify which one of PAM, kerberos_v4, passwd, shadow you wish to
use. If PAM is the authentication you desire for example, you would
type:
sasl_passwd_check: pam
instead of the line above
7.2. Creating the necessary directories
This list of instructions will set up all the directories necessary
for imap.
1. mkdir /var/adm
2. touch /var/adm/imapd.log /var/adm/auth.log
3. mkdir /var/imap /var/spool/imap /var/imap/srvtab
4. chown cyrus /var/imap /var/spool/imap /var/imap/srvtab
5. chgrp mail /var/imap /var/spool/imap /var/imap/srvtab
6. chmod 750 /var/imap /var/spool/imap /var/imap/srvtab
7. su cyrus
You are now the user cyrus. This is necessary for the files to have
the correct owner and group. Continue:
1. tools/mkimap
2. cd /var/imap
3. chattr +S . user quota user/* quota/*
4. chattr +S /var/spool/imap
5. exit
You are now root again. The last command:
chattr +S /var/spool/mqueue
7.3. More configuration file editing
1. Edit /etc/services and check for the following lines. If they do
not exist, add them:
pop3 110/tcp
imap 143/tcp
imsp 406/tcp
kpop 1109/tcp
sieve 2000/tcp
2. Edit /etc/inetd.conf and comment out any imap and pop3 lines and
add the following:
imap stream tcp nowait cyrus /usr/cyrus/bin/imapd imapd
pop3 stream tcp nowait cyrus /usr/cyrus/bin/pop3d pop3d
3. Edit /etc/sendmail.mc with care not to add extra spaces and add the
following lines(do not copy and paste directly from this text as
the tabs won't be added correctly):
MAILER(local)
MAILER(cyrus)
define(`confLOCAL_MAILER',`cyrus')
LOCAL_RULE_0
R$=N $: $#local $: $1
R$=N < @ $=w . > $: $#local $: $1
Rbb + $+ < @ $=w . > $#cyrusbb $: $1
Use tabs to separate the data (i.e. R$=N has three tabs between it and
$: $#local $: $1) Then run: m4 sendmail.mc > sendmail.cf
4. Edit /etc/group and add the user daemon to the mail group.
7.4. If you use postfix instead of sendmail
Postfix is a mail-deliver alternative to sendmail. Most linux
installations use sendmail by default. If you use postfix, ignore
configuration #3 from the last section and uncomment or add the
following line in /etc/postfix/master.cf
cyrus unix - n n - - pipe flags=R user=cyrus argv=/usr/sbin/cyrdeliver -e -m ${extension} ${user}
Also add or uncomment this line in /etc/postfix/main.cf
local_transport = cyrus
8. Cyrus IMAP Implementation
8.1. Add the cyrus administrator
Run the following command to set up a user for cyrus
/usr/local/sbin/saslpasswd cyrus
8.2. Testing Cyrus IMAP
1. killall -HUP inetd
2. su cyrus
3. imtest -m login -p imap localhost
Enter your password. If you see something like:
(L01 OK User logged in means you're in)
Then the setup has been successful. Type
. logout
to log out.
8.3. Setting up users
Still as the user cyrus, type the following commands. They will set up
the mailbox(es) for each user. Fill in the username where you see the
(username).
1. cyradm localhost
2. cm user.joebob (for all the user joebob)
3. quit
4. exit (back as root)
Now as root, enter a password for each username
saslpasswd (username)
8.4. Delivery database pruning
If you don't periodically prune the database of deliveries, you can
fill up your file system. Adding a cron job which will run once a day
is one way to do this. That involves going to /etc/cron.daily and
creating a file named cyrus-imapd. Inside that file, put the following
two lines of code:
#!/bin/bash
su cyrus -s /bin/bash -c '/usr/cyrus/bin/deliver -E 3'
Make this script executable by running: chmod 755 cyrus-imapd
You should also create the deliverdb directory to store database files
in:
mkdir /var/imap/deliverdb
8.5. Finishing up
Reboot the machine to make sure that everything has been restarted
under the new configuration
9. Troubleshooting
If you encounter any errors, you can do the following to view error
messages:
1. tail /var/log/messages
2. tail /var/adm/imapd.log
3. killall sendmail && sendmail -bd -X /root/error.log (then read
/root/error.log)
If you are having "virtual memory exhausted errors" when compiling,
running
ulimit -d unlimited
as root has been reported to work.